PURPOSE: To obtain a new compound useful for treating hyperglycemia.

CONSTITUTION: The objective compound of formula I [R1 to R3 each is a lower alkyl; R4 is H, a lower alkyl, a nitrogen-contg. unsaturated heterocycle or a (substituted) aryl; X and Y each is a lower alkylene; n is 0 or 1], e.g. 2-(4- bromophenyl)-6-(2-hydroxy-2-methylpropoxy)-4-methyl-1,1-dioxo-4H-benzo[e][1,2,4 ]thiadiazin-3-one. The compound of formula I can be obtained by reaction of a compound of formula II with a compound of formula R2MG-A (A is halogen). The raw material compound of formula II, which is also a new material, can be obtained by starting from reaction of a compound of formula III (R6 is a lower alkoxyl) with a compound of formula H2N-(Y)n-R4.